Cohort Size and the Marriage Market: Explaining Nearly a Century of Change in U.S. Marriage Rates

We propose an explanation for almost a century of changes in U.S. marriage rates, in three stages. First, we show that cohort size alone can account for nearly all variation in marriage rates since the 1930s for both black and white populations. Specifically, increases in cohort size reduce marriage rates, whereas declines in cohort size have the opposite effect. We use plausibly exogenous differences in states' mobilization rates during WWII as a source of variation in cohort size to argue for a causal relationship. Next, we develop a dynamic search model of the marriage market that qualitatively generates this observed relationship, and derive a testable implication about cohort size's effect on partners' age differences. Finally, we estimate the model and investigate its consistency with the data. We fail to reject it using the derived implication, and find that it can quantitatively explain much of the observed variation in marriage rates.